We propose to examine the relation of chronic lead (Pb) exposure to adverse pregnancy outcome and infant development in a unique community surrounding a Pb smelter in Titova Mitrovica, Yugoslavia. Subjects will also be studied in Pristina, a non-Pb- exposed town 25 miles away. No other locations in the world provide such a wide range of Pb exposures. Work in progress examines the effects of Pb exposure on pregnancy outcome in approximately 616 women in Mitrovica and 898 in Pristina Preliminary data from a total of 1106 women, examined at 12-20 weeks gestation, indicate that blood lead (BPb) concentrations in Mitrovica range from 2-57 ug/dl, with a mean of 17.4 ug/dl; in Pristina, the mean BPb is 5.4 ug/dl. Questionnaire data reassure us that our populations are comparable with regard to maternal and paternal age and education, maternal height and weight, number of previous pregnancies, ethnicity and measures of socioeconomic status. We will determine whether exposure to Pb is associated with an increased risk of selected adverse pregnancy outcomes: late spontaneous abortion and stillbirth, premature delivery, intrauterine growth retardation and congenital malformations. Blood samples from women enrolled in the study reveal a strong correlation between BPb at midpregnancy and at term. Likewise, there is a strong relation between maternal BPb at term and umbilical cord BPb. In Mitrovica, mean cord BPb is 20.6 ug/dl; in Pristina it is 5.6 ug/dl. We propose to assess infant development in relation to pre- and postnatal Pb exposure. In Mitrovica, we will follow during the first 3 years of life 3 subsets of infants: a) 210 with the highest cord BPb's; b) 136 with the lowest BPb's, and, c) a sample of 136 infants from infants with moderate BP's. Two matched control groups of infants in Pristina will also be followed. The infants will be evaluated for BPb and measures of physical, behavioral and cognitive-linguistic development at 6 month intervals. Preliminary data are presented for the first 159 infants who have been evaluated at 6 months of age.